Air cooler



April 9, 1940.v s, M, K,1.\| |N 2,196,310

AIR COOLR Filed Aug.".25, 1936 2 Sheets-Sheet 1 Inventor.

' Samue/ A4. Ka//n y www Horneys. z

April 9, 1940. s'. M. KALlN AIR COOLER Filed Aug. 25, 195e 2 sheets-sheet A Q. 7ll//Ill/lll/l/lllII/lllllllllIlllIII/llllllllllllllllllllllllllllllllIlllllIlllll/lllllll1/1111111 BIZ-q l 5l Fifi-tl 4.

Patented Apr. 9, 1940 UNITED STATES AIR COOLER Samuel M. Kalin,

Los Angeles, Calif.

Application August 25, 1936, Serial No. 97,751

21 Claims.

My invention relates to an air cooler in which the cooling agent is preferably solid carbondioxide normally known as dry ice. In the use of frozen carbon-dioxide as a cooling medium one of the diliculties is to prevent too rapid a melting and evaporation to gas of the ice. This causes in most cases too great a lowering of temperature, especially when the cooling medium is used in an enclosed chamber, resulting where the cooling is used for various perishable products of freezing certain of the products. However, various attempts have been made to use carbon-dioxide ice as a cooling medium in which air has been cooled by direct contact with the ice or by transference of heat between a vessel containing the ice and the air to be cooled, such air later being circulated for refrigerating purposes.

My invention is principally developed for use in refrigerating trucks having closed bodies and used for transporting perishable produce including such commodities as the transportation of beer.

An object and feature of my invention is a self contained refrigerating unit for cooling the air, such air being positively circulated by a blower or the like and in which a combination heat retarding medium and heat transfer agent is interposed between the circulating air and the carbondioxide ice. This prevents the circulating air coming directly into contact with the ice or in direct contact with the outside of a vessel which contacts the ice, which practically amounts to the same thing. By having @e vessel containing the ice surrounded by a heat transfer medium which also retards the transfer of heat, the ice is prevented from melting too rapidly and a larger surface may be exposed to the circulation of air and the heat transf-erred from the flowing air to the transfer medium. An object and feature therefore of my invention is surrounding the vessel containing the carbon-dioxide gas, at least as to the sides and bottom by a layer of brine such as calcium-chloride brine, this being conned by an outside wall spaced from the walls of the ice receptacle. The air is then circulated over the outside wall of the brine container. The brine absorbs the heat from the air and such heat is absorbed from the brine by the ice causing a melting thereof and thus developing the refrigerating action.

Another object and feature of my invention is an arrangement for preventing an explosion of the ice in a closed receptacle which sometimes occurs from too rapid gasification, therefore I (Cl. Gil-91.5)

provide a safety valve releasing the gas at the desired pressure. This safety valve is exposed to a relatively warm atmosphere so that there is 4but little danger of the valve freezing and thus becoming inoperative.

Another object and feature of my invention is in circulating the air in a heat insulated box or the like, this box containing the ice receptacle and the brine container surrounding the same and having a relatively large space for the circulation of air, such air being preferably blown in one end of the box and out the opposite end. To facilitate the heat transfer I provide a large number of radiating fins secured to the wall of the brine container and arranged in a somewhat staggered and criss-cross manner so that the air owing around the outside wall of the brine container is brought into intimate contact with the heat transfer ns.

Another feature of my invention provides the combination of a thermostat control for an electric motor to operate a blower and closure louvers automatically operated in conjunction with the flow of the air, that is, with the operation of the motor so that when the temperature in the chamber to be refrigerated is sufficiently cool, the blower is stopped and the louvers at the air discharge are closed. Thus the air is conned in the air circulating space of the refrigerating box and this gradually becomes chilled to a very low temperature so that immediately on starting the blower again when the temperature in the refrigerated chamber rises, a cold blast of air is immediately disseminated into such chaml ber. A detail feature of my invention includes a drain outlet with a valve for moisture condensing in the air circulating compartment.

My invention is illustrated in connection with the accompanying drawings in which:

Fig. 1 may be considered as a longitudinal ver- 40 tical section taken substantially on the line I-l of Fig. 2 in the direction of the arrows.

Fig. 2 is a transverse section on the line 2-2 of Fig. 1 in the direction of the arrows.

y Fig. 3 is a partial elevation' taken in the direc- 45 tion of the arrow 3 of Fig. 1 showing the air. deector at the air inlet end and also the arrangement of the heat radiating fins.

Fig. 4 is an end elevation of a portion of the device illustrating the arrangement of the louvers. 1

Fig. 5 is a perspective detail of one of the heat radiating iin-bars.

Fig. 6 is an assembly View showing the device in side elevation as installed in a. refrigerating truck, the body of the truck being illustrated in longitudinal section.

In constructing my invention I build up a box structure I I. This has outside walls I2 in which the side walls are indicated at I3 and I4, the end walls at I5 and I6 and the bottom at I1. This box has an inset shoulder I8 slightly below the top cover plate I9. Extending downwardly from the inner edge 28 of the cover plate is construct/ed the ice receptacle 25. This is indicated as having side walls 26 and 21 and end walls 28 and 29 and a bottom 38. The end walls and the bottom connect by concave curves 3|. The side walls and the bottom preferably have right angular corners 32. An annular flange 33 is used for securing the ice receptacle to the top cover plate |9.

The brine receptacle 35 utilizes the wall of the ice container and an ,outside wall structure 3B. This has parallel sides 31 and 38 and also parallel ends 39 and 48 with a bottom 4| connected by curves 42 to the ends. This also has a marginal flange 43 for attachment to the plate I9. The brine container is preferably of equal thickness throughout, that is, the distance between the outside Wall of the brine container and the wall `of the ice receptacle are the same distance apart at the ends, the sides and the bottom. The plate I9 is provided with a threaded filler opening 44, this being sealed after the brine container is filled with brine by the closure plug 45 the top of the plug being either ush with or below the top surface of the plate 9.

The air circulating compartment designated by the assembly numeral is deiined by the outside wall structure of the brine container and the inside walls 5I of the box. This inside wall has opposite sides 52 and 53 and ends 54 and 55 and a bottom 56. A concave curve 51 joins the bottom and the ends but the junction of the bottom and the sides is preferably by a right angle 51. A marginal rim 58 is used for attaching the wall structure 5I to the plate I9. An air inlet structure 59 preferably formed rectangular in cross section connects the end wall 54 and passes through an opening in the outside end wall I8, being secured to both of these walls and thus providing an intake passage 68. At the opposite end there are ,preferably a series of air outlet tubes 6| secured to the end wall 55 and to the outside end wall I5. The arrangement shows in Fig. 4 four of such openings located in a horizontal row, A packing of heat insulating material 82 such as cork fills between the inner and outer walls of the box. air passage structure and the outlet air tube 8|, this material being packed closely against the top plate I9.

An air deector is formed of a dome-shaped plate 66, this preferably curved approximating part of a sphere and has horizontal upper and lower edges 81 and 68 and side edges 59 and 18 (note Fig. 3). The upper edge 61 and the two I side edges 69 and 'I8 are secured to the end wall 48, the plate being located in the air circulating compartment 58 directly opposite the inlet air passage 68. The lower edge 68 is spaced as in-` It surrounds the inlet.

and 19. A series of louver plates 88 are each secured on the longitudinal pivot 8 I, the pivot being rotatably mounted in the end elements 18 and 19. The louvers are connected by a vertical link 82 which is pivoted to each louver as indicated at 83 to force all these louvers to operate at the same time. An operating rod 84 (note Fig. 1) is slidable through a guide 85 mounted in one of the air discharge tubes 6|. This rod has a downturned inner end 86 on which is mounted a baffie plate 81 in the form of a disc, this being directly in the path of the circulating air and adapted to open the louvers by the flow of air, the levers automatically closing by the action of gravity when no air is being blown through the air compartment.

A heat conducting n assembly designated by the numeral 98 consists of heat radiating fins in which there are a series 9| secured to the opposite sides 31 and 38 of the outside wall of the brine container, this also being the inner wall of the air circulating compartment. There is another assembly of ns 82 extending along the bottom 4| and the curved corner portions 42 of the outside wall of the brine container, this also being the inside wall of the air compartment. The fins are designed to extend longitudinally in the direction of the ow of air.

I flnd a simple and effective manner of constructing the fins is by making a plurality of fln-bars 93 (note Fig. 5), these having a web 94 and a flange 95 at right angles, the flange being used for securing by winding or the like to the outside wall of the brine container. There are a plurality of divergent individual fin plates 9G. These are formed by having slits 91 formed in a portion of an angle which includes the web 94 and the flange 95, thus separating the individual n plates which are bent at an angle on opposite sides of the web. Adjacent fin-bars are assembled as shown by the full and the dotted lines as shown in Fig. 5 in which it will be noted that the individual fin plates of adjacent bars intersect and fit in the space 98 between the slit edges at alternate fin plates. This forms a type of honeycomb arrangement of the ns by making a series of longitudinal air passages between the individual fin plates and also between the webs of adjacent fin bars.

A removable cover structure |88 (note Figs. 1 and 2) has an outside sheet metal casing IUI which includes a top |82, downturned ends |83 and sides |84. The downturned ends are designed to fit adjacent the shoulders I8 of the lower part of the box. This cover has a layer of wood |85 immediately under the top |82, a layer of cork |86, a felt strip |81 and a cloth such as canvas bottom |88, the canvas being carried up at the margins as indicated at |09.

The cover is secured to the bottom part of the box by providing bolts ||8 hinged at to the side walls I3 and I4 of the box, these hinges beingr close to the shoulders 8. The bolts iit through split ends 2 of cross-channels ||3 which are secured to the top metal |82 of the cover. Nuts ||4 on the bolts clamp the cover tight to the lower part of the box and form a substantially gas-tight seal where the canvas I 81 contacts the top plate I9 of the lower part of the box.

The relief or safety valve designated by the assembly numeral |28 comprises a tube |2I which extends through the cover |88, there being preferably a board or metal plate |22 below the canvas and secured in place by a nut |23 threaded on the tube. The upper end of the tube is provided with a relief check valve |24, this being illustrated as a ball valve held seated by a spring. This construction locates the check valve entirely outside of the box structure and remote from the ice chamber. Also the valvevis exposed to the air of the room being cooled where the whole box is in the room or where the box is mounted in a refrigerating truck as shown in Fig. 6. This relief valve is exposed to the outside air.

Therefore when the pressure of the gas from thedry-ice blows off the gas vapors, there is but little danger of the safety valve freezing on account of the warming action of the external air.

The air is preferably circulated by a blower operated by an electric motor |3|. This motor receives energy from a source of power |32 indicated as a battery (note Fig. 1) and in this circuit there is a thermostat |33, the thermostat being located in the room or chamber which is being refrigerated and is adjusted to open the circuit when the temperature is reduced to a predetermined range.

An installation of my invention is shown in Fig. 6 in which the body of a refrigerator truck is designated by the numeral |35. This is provided with an opening |36 in the roof and the box is preferably provided with angle irons |31 securing the box structure to the roof by bolts or rivets |38. It will be noted by reference to Figs. 1, 2, 4 and 6 that the cover |00 is entirely above the roof so that it may be removed to expose the ice receptacle for re-icing the equipment. The circulation of airis more or less in the direction of the arrows |39 (note Fig. 6). I find it preferable to mount the refrigerating box adjacent the rear end of the'truck and have the draft of cold air blown forwardly. As the cold air tends to descend it flows -downwardly towards the bottom of the truck, the load being packed in the truck in such a manner as to permit the circulation of air. 'I'hen the air which has been warmed is sucked up by the blower along the rear portion of the truck and again blown through the circulating air compartment. The air deflector plate 65 prevents a direct contact of the air as blown in on the outside of the brine container but causes the air to be deflected downwardly and to both sides. A drain pipe |40 is connected through the wall 52 into the air compartment at the lower 'part of the bottom 56 and is shown as passing through the outside wall |4 and having a drain-cock |4| thereon so that any condensation from the air in the air compartment, if this becomes excessive, may be drained out of such compartment.

Various changes may be made in the details of the construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. In an air cooler comprising in combination a container for a liquid heat transfer agent having an inner and an outer wall and forming a hollow ice receptacle inside of the inner wall open at the top, an air compartment formed by the outer wall of the liquid container and having an outer wall structure with a heat insulation applied thereto, means to circulate air through the air compartment to bring the air into a circulating contact with the outer wall of the liquid container, a heat insulating cover for the open top ice receptacle, said cover also forming an insulating cover for a portion of the liquid container and of the air compartment,

means to form a substantial gas tight joint at the top of the ice receptacle and a blow ofi. valve connected to said ice receptacle.

2. In an air cooler the combination of a liquid container for a liquid heat transfer agent having inner and outer walls, the inner walls forming an open topped ice receptacle with sides, ends and a bottom, the liquid container being substantially of equal thickness between its inner and outer walls, a containing structure having heat insulation therein with a space providing an air compartment on the outside of the liquid container, means to blow air through the said space, there being an intake passage and outlet openingsthrough the structure having the insulation and a gas blow off valve from the ice receptacle.

3. In an air cooler as claimed in claim 2, the said structure having the insulation being constructed somewhat box-like with a horizontal top, the upper portion of the liquid container being in alignment with such top, an insulating cover for the top of the box-like structure with means to form a substantially gas tight joint at the periphery of the ice receptacle, the gas blow oif valve being connected through the cover to the ice receptacle.

4. In an air cooler, the combination of a boxlike structure having a liquid container with inner and outer walls and a bottom, the inner walls of the container defining an ice receptacle open at the top, the box-like structure having a top closure element except for the open top ice receptacle, insulating material in the`box and spaced from the outside of the liquid container and defining an air compartment for circulation of air, an inlet passage at one end and outlet openings at the opposite end with a blower connected to the inlet passage, a cover having insulation secured to the top of the boxlike structure and forming substantially a gas tight seal, a gas vent from the ice receptacle through the said cover, the liquid container being of substantially equal thickness whereby a heat transfer is developed from the circulating air through the liquid to the ice in the ice receptacle.

5. In an air cooler as claimed in claim 4, the blower forming a means for preventing circulation of air when the blower is at rest and an automatically operative closure element for the air outlets forming a closure therefor on the cessation of the circulation of air whereby the air in the air compartment may become chilled to a low degree by transference of heat through the liquid to the ice.

6. In an air cooler as claimed in claim 4, the inside wall of the air compartment defined by the outside of the liquid container having two opposite ends, sides and a curved bottom for the flow of air, a baffle at one end opposite the inlet passage of air to deflect air sidewise and downwardly.

'7. In an air cooler as claimed in claim 4, the outside of the liquid container on its sides and bottom having heat transfer fins, said fins having a longitudinal web and n plates diverging laterally from said web and arranged for adjacent n plates to diverge in the opposite directions, the said fins and webs being located in close proximity whereby the fin plates of adjacent webs overlap.

8. In an air cooler, a structure having a Wall with a heating transfer medium at one side, fin bars consisting of long plates having webs at right angles to the wall and secured thereto and individual fin plates diverging therefrom on opposite sides of the plane of the webs and means to circulate air on the outside of the wall to contact with the web and the n plates, alternate fin plates diverging in the same direction.

9. In an air cooler as claimed in claim 8, there being a plurality of fln bars secured to the wall with the webs parallel and positioned to have certain of the n plates overlapping in a closeover manner to form a honeycomb type of structure and means to ow air longitudinally of the webs and of the planes" defined by the iin plates.

10. In an air cooler, the combination of an insulated structure having an air compartment with an inlet passage and outlet openings for circulation of air, a liquid heat transfer container positioned in the insulated structure, the outside wall of the liquid container forming the inside wall of the air compartment, the inside wall of the liquid container forming a receptacle for carbon-dioxide ice, a vent structure from the ice receptacle to discharge the gas from vaporization of the ice completely outside of the said structure and outside of the air compartment.

11. In an air cooler as claimed in claim 10, louvers forming a closure for the outlet openings and means tov operate said louvers when the air circulates through the air compartment and to close the louvers when the air ceases to circulate.

12. In the method of air cooling, circulating a body of air confined in an air compartment on the outside of a quiescent brinecontainer to transfer heat `from the air to quiescent brine in such container, transferring heat from the brine to carbon-dioxide ice in contact with one side of the brine container, the air being always entirely out of contact with the ice, causing a cessation of the ow of air whereby quiescent air in the said compartment becomes chilled to a low degree, then again circulating the air whereby cold air of low temperature is forced out of the air compartment and discharging carbon dioxide gas from the carbon dioxide ice entirely away from said body of air.

13. In the method of air cooling as claimed in claim 12, distributing the air circulated from the confined air compartment in a relatively large chamber to be refrigerated, drawing air from one part of said chamber and circulating the air through the confined air compartment until the whole of the chamber is reduced to a desired low temperature, then causing the cessation of the flow of air until the temperature in the refrigeration chamber rises to a higher temperature and again circulating the air.

14. In the method of refrigerating a relatively large refrigeration chamber comprising circulating air through an air compartment on the outside of a. quiescent brine container to transfer heat from quiescent air to the brine in such container, transferring the heat from the brine to carbon-dioxide ice in Contact with one side of the brine container, the air being always out of contact with the ice, causing a distribution of the air circulated over the outside of the brine container through substantially all parts of the chamber to be refrigerated to reduce the temperature in said chamber to a desired low temperatureand discharging carbon dioxide gas from the carbon dioxide ice entirely away from said air compartment and away from said chamber.

l5. In the method of refrigerating as claimed in claim 14, circulating the air through an air compartment on the outside of lthe quiescent brine container, causing a cessation of the flow of air through said compartment and retaining the air in the compartment quiescent when the refrigeration chamber is chilled to the desired low temperature, then on the increase of temperature in the refrigeration chamber again recirculating the air through the air compartment, the air in the air compartment being adapted to be chilled during a period of cessation of circulation to a temperature much below that of the refrigeration chamber.

16. In the method of refrigerating a relatively large insulated refrigerating chamber comprising confining a body of air in a confined air compartment on the outside of a quiescent brine container to transfer heat from the air to quiescent brine in such container, transferring heat from the brine to carbon-dioxide ice in contact with one side of the brine container, the air being always out of contact with the ice, circulating air through the air compartment and distributing the chilled air through the refrigeration compartment and continuing the circulation by drawing air from the refrigeration compartment to the confined air compartment until the temperature in the refrigeration compartment reaches a desired low degree, then causing a cessation of the flow of air through the confined air compartment to produce a quiescence of the conned air whereby such quiescent air becomes chilled by contact with the outside of the brine container to a temperature much below that of the air in the refrigeration chamber, then when the temperature in the refrigeration chamber rises above that desired for refrigeration, again re-circulating the air through the confined air compartment, the air which has been conned and chilled to a low temperature being adapted to cause a relatively quick lowering of temperature in the refrigeration chamber and discharging carbon dioxide gas from the carbon dioxide ice entirely away from said compartment and chamber.

17. In the method of refrigerating as claimed in claim 16, when the carbon-dioxide ice is exhausted, re-plenishing with additional similar ice without changing the air by admission or extraction from the refrigeration chamber or the confined air compartment.

18. A refrigerating plant comprising in combination a relatively large refrigeration chamber having insulating walls, a removable insulating cover in one of the walls, an ice receptacle having one side exposed to the removable cover for inserting dry ice in such receptacle, a container for a liquid heat transfer agent having one wall defined by the wall of the ice receptacle and an outer wall substantially parallel thereto, means to flow air from the main body of the refrigerating chamber over the outer wall of the liquid container to effect a transfer of heat from the air of the refrigeration chamber to the liquid in the container and to the carbon-dioxide ice in the ice receptacle, the said cover being adapted for removal and replacement without any change of air in .the refrigeration chamber or air flow means and means for exhausting the gas from the dry ice directly from the ice receptacle to atmosphere.

19. A refrigerating plant comprising in combination a relatively large refrigerating chamber having insulating walls with an opening in the top wall, a box structure fitted in said opening, said box structure having an ice receptacle for carbon-dioxide ice, open at the top and having an insulating cover over the ice receptacle, a liquid container for a liquid heat transfer agent having inner and outer walls, the inner wall being defined as the wall of the ice receptacle and the outer wall being substantially parallel thereto, heat insulation in the box spaced from the outside wall of the liquid container and forming therebetween an air circulating compartment with an air inlet opening communicating with the refrigeration chamber at'one portion of the box and an air outlet opening communicating with the refrigerating chamber at another part of the box, means to ilow air from the refrigerating chamber through the air circulating compartment for a transfer of heat from the air to the liquid and the liquid to the ice whereby the temperature in the refrigeration chamber may be lowered to a desired degree and means for exhausting the gas from the dry ice from the ice receptacle entirely away from the air circulating compartment.

20. A refrigerating plant as claimed in claim 19, means to cease the flow of air through the air circulating compartment, said means forming a substantial air closure at the air inlet opening and means to form an air closure at the outlet opening whereby the air in the circulating compartment remains still and may become chilled to a temperature much lower than that in the refrigeration chamber whereby on again starting the circulation of air, a body of air of decidedly low temperature is forced into the refrigerating chamber.

21. In the art described, confining carbon dioxide ice within a container having a quiescent liquid of low freezing point, surrounding at least part of the container with a body of still air restricting the transfer of heat by the air away from said container by conduction, convection and radiation, transferring heat from the air to the said liquid and from the liquid to the ice and discharging carbon dioxide gas from the carbon dioxide ice entirely away from said body of air, periodically developing a circulation of the air to change the air in contact with the container to produce a transference of heat from the moving or circulating air to the liquid and from the 'liquid to the ice.

SAMUEL M. KALIN. 

